1. Technical Field
The invention relates to a method for the testing of turbochargers in which a turbine of the respective exhaust-gas turbocharger is driven by means of air which is under pressure, and the test being carried out at least with the inclusion of measurement quantities on the compressor of the respective turbocharger, or in which a turbine of the respective exhaust-gas turbocharger is driven by means of compressed air, and the test being carried out with the inclusion of at least measurement quantities determined on the respective exhaust-gas turbocharger.
2. Prior Art
The invention entails testing exhaust-gas turbochargers by what is known as cold testing. In this respect, it is already known to operate the turbine of the exhaust-gas turbocharger not with hot combustion air from an internal combustion engine, but with compressed air which is at ambient temperature. In known cold tests of exhaust-gas turbochargers, for this purpose, the turbine is driven with compressed air, specifically at a low rotational speed outside the turbine characteristic diagram. The compressor in this case runs empty, that is to say does not generate any compressed air on the delivery side. In this known cold test, the exhaust-gas turbocharger is not to be tested under load. In practice, therefore, only a mechanical running test can take place. Since, in the known cold test, the exhaust-gas turbocharger cannot be operated in the turbine characteristic diagram, its performance and operating characteristic cannot be determined. This is a disadvantage, above all, when, as in V-type internal combustion engines with a plurality of exhaust-gas turbochargers, it is customary to assign an exhaust-gas turbocharger to each cylinder bank, that is to say the internal combustion engine has two exhaust-gas turbochargers. The two exhaust-gas turbochargers are to be capable of being operated as synchronously as possible. Even where basically identical exhaust-gas turbochargers are concerned, their efficiencies and operating characteristics differ from one another on account of various influences, in particular tolerances. The different operating characteristics of exhaust-gas turbochargers which are identical per se do not permit synchronous running. The aim, therefore, is to select for an internal combustion engine having a plurality of exhaust-gas turbochargers those exhaust-gas turbochargers which have virtually the same characteristics. For this purpose, in the cold test, the operating behavior of each exhaust-gas turbocharger must be capable of being tested, which known cold tests of the type initially described do not permit.
Proceeding from this, the object on which the invention is based is to provide a method for the testing of exhaust-gas turbochargers, whereby even measurement quantities of loaded exhaust-gas turbochargers can be detected in the cold test.